Drawing apparatus



Dec. 27, 1,938. v W; J, EVANS 2,141,350

DRAWING- APPARATUS Filed June 2, 1937 2 sheets-'shea' 1 Fig-. 42 4I- [0 Dec. 27, 1938. 'w. J, EVANS DRAWING APPARATUS Filed June 2, 1957 2 Sheets-Sheet 2 Il.. A 1

/A/ VEA/701? wf M Patented Dec. 27, 1938 PATENT OFFICE nnAwiNG APPARATUS William James Evans, Bulwell, Nottingham,

. England Application Jlllle 2, 1937, Serial No. 146,077

In Great Britain June 5, 1936 2 Claims.

This invention is for improved drawing apparatus such as may be employed by draughtsmen for machine drawing. Anobject of the invention is to provide vapparatus in which, by a simple adjustment, straight lines may be produced at various angles without the use of a protractor, or lines parallel with any angle.

Apparatus according to the present invention comprises a drawing board, a straight edge mov. able over the face of said board, and means whereby when said two members are assembled in a co-operating position, relative rotation can be effected therebetween. More particularly the apparatus embodies a drawing board having, in lcombination therewith, a straight edge movable over the paper-receiving surface thereof and a pivotal connection between the board` and straight edge whereby relative rotational movement can be eiected between the two about an axis normal to the surface of the board or paperreceiving surface.

In a preferred arrangement the drawing apparatus in this invention comprises a base, a circular paper-receiving turntable mounted on said base to rotate about a central axis, a straight edge or T-square extending across the paper-receiving face of the turntable and movable laterally over same, and means for guiding said straight edge in its movement. Preferably there are two par- `allel guides for the straight edge, and the guide or guides are advantageously provided with a linear scale or scales, while the turntable has associated therewith an angular scale whereby various annular positions of the straight edge on the paper can be obtained.

Other features of the invention are embodied in the construction hereinafter more fully described and set forth in the accompanying claims. For the purpose of more fully describing the nature of this invention reference will now be made to the accompanying drawings, wherein:-

Fig. 1 is a plan of an apparatus in accordance with this invention.

Fig. 2 is an` enlarged vertical section on 2-2 451 Of Fig. 1.

Fig. 3 is a sectional plan on 3--3 of Fig. 2.

Fig. 4 is a vertical section illustrating the pivotal mounting of the turntable.

Fig. 5 is an enlarged sectional plan of a device for fixing the turntable from rotary movement, and

Fig. 6 is an enlarged vertical section oi a pencil holder fitted to the straight edge, said section being taken on line 5--6v of Fig. 1.

In one method of carrying out the invention as shown in Figs. 1 to 3 of the drawings there is a rectangular base ID of wood or other suitable material having upstanding peripheral walls Il whereby the base is of shallow box or tray formation, the four corners of the upstanding walls being curved at their inner edges so. that. the in` terior of the base is circular. Within the recess. in said base I0 is mounted a circular turntable I2, the upper horizontal face. of which is substantially level with the top face of the upstanding walls Il. This turntable is mounted to rotate on the base on a central axis, and to this end said turn. table has vfixed thereon at its centre a short stub axle or pivot I3 which enters a circular upstanding boss I4 on the base I0, there being a yroller bearing or the like I5 between the pivot alld. boss (Fig. 4). On the underside of the turntable there are also a plurality of suitably spaced rollers or runners I6, the bearings I 'I for which may be fixed to blocks I8 secured to the underside of the turntable, said rollers I6 running on an annular metal disc I9 screwed or otherwise secured to the base II). By this means the turntable is free to rotate but is held from rocking movement. On the turntable I 2 is adapted to. be fixed by any Suitable means. the drawing paper 2.0. For ex.- ample e pair Of. parallel clamping Strips- 2! may be provided for the paper, said strips coacting with recesses 2 2 in the upper face of the turntable and the clamping of the paper being effected by manipulation 0f headed screws 2.3V enacting with internally threaded sockets 24 screwed to the undersde 0f the tnrnt, ble, a 1011 spring. 25 encircling the stem of each screw 23 between a washf er 26 and the top face of the socket 2,4. Qn re-v leasing the screws 23 the Springs 25 press upy wardly the clamping strip 2 I out oi the recess 22 so as to permit of the'edge of the paper being inserted beneath the strip, after which the screwis tightened up-and the edge ofthe paper is clamped between the strip 21| and the recess 22A. Other means may, however, be employed for fixing the paper in position 0n the turntable.

Projecting up at each of two opposite side edges of the base I0 above the walls II is a guide 2,1 for a straight edge, T-square or the lilge 28. Each guide 21 is a-djustably secured in position, and one method of accomplishing this will` now be described. An angle bar 29 is screwed to the top face of each of the two opposite side walls I ,I of the base or to a plate thereon and within each angle bar is iitted a guide bar 21, said guide bar being secured to the wall II by a plurality of screws 30 passing through elongated slots l3l (Fig. 3) in the bar, which slots permit Qf lateral adjustment of the bar.` To elect the lateral ads justrnent a plurality of screws 3,2 pass through and are freely rotatable within the upstanding flange of the angle bar 29 and have av screwing engagement with the bar 21, there being preferably a disc or washer 33 encircling the screw between the angle bar and the opposing face of the guide bar 21. The straight edge 28 extends between the two guide bars 21, said straight edge having a right angle portion or head 34 at each bars are provided with projecting ribs 35 which coact with grooved rollers 3S mounted in metal bearings 3l within recesses 38 formed in each head34 of the straight edge. When, therefore, the straight edge is fitted in position extending across the paper-receiving surface of the turntable l2 the guidesk 2l are laterally adjusted by releasing the iixing screws 30, rotating the adjusting screws 32 and afterwards tightening up said ixing screws 30. c

A linear scale 39 is fitted on the top face of each guide bar 21, the straight edge 28 being provided with suitable indicating pointers or vthe like 40' Vcoacting with said scales so that the straight edge can be moved'laterallyrover the turntable to a measured distance in either direcv tion.

The turntable l2 is provided et its periphery with an angular scale 4I preferably in the form Y of a thin annular plate with radiating lines and appropriate numerals, say from 0 to 90 as on a protraotor, thev arrangement being such that as the `turntable is rotated on its central axis the peripheral scale moves relatively to a iixed index mark such as is indicated at 42 in Fig. l, and lines at varying or diierent angles can be drawn.

For Yexample if a line is drawn along the straight edge with the numeral 0 registering with the index lmark 42 and a further line is required to be drawn at say 30 to said iirst line, then the'table is rotated until the numeral 30 registers with the index mark, it being understood that if the tableY isrotated in one direction the line at 30is drawn beneath the rst drawn line, whereas by rotating the table in an opposite direction the second line is drawn above the first line.` Y

In order to hold the turntable from movement `a manually operable brake is provided. This brake may comprise a brakes'hoe 43 (Fig. 5) coacting with the peripheral edge of the turntable |.2 and provided with suitable braking material, said brakeshoerbeing Vfreely mounted'at the end of a screw 44 threaded into an internally screwed sleeve 45 xed by an attachment plate 46 to one of the walls of the base i0, said screw 45 having a milled head or similar head 41 whereby same is rotated. The arrangement is such that when the screw 44 is rotated in one direction the brakeshoe 43 is pressed into frictional gripping engagement with the periphery of the turntable I2 and when screwed in an opposite direction the brake is released. Advantageouslycalso the brake has associated therewith a headed locking pin 4B which conveniently passes axially through the screw 44 and is adapted .releasably to coact with A any one of a plurality of suitably spaced holes or notches 49 in the periphery o-f the turntable I2 or any Ysmall attachment plates secured thereto. Advantageously the notches 49 are distributed at intervals of say 45 or 90 around the turntable sothat at any one ,of these positions 4the turntable can bepositively locked by'pushing inwardly the pin48.

If desired, the straight edge 23 may have tted theretoa holder for a pencil or equivalent drawtween theunder side of said sembled within a sleeve 55 which also has a hole therethrough, the tightening-upV of the nut 53` Y causing the pencil'to be gripped between the sleeve 55.and the holder within said sleeve. It will be appreciated that thepencil may be adjusted to extend either vertically or at a suitable angle. Alternatively,V the pencil holder or the like may be mounted to slide or be otherwise adjustable along the straight edge. The mounting of a pencil or the like on the straight edge enables lines` to be drawn on the paper by the simple movement of the straight edge'over same. Also by suitablefadjustment ofthe pencil and of the straight edge, circles can be drawn on the paper by rotation of the turntable.

Y A plate or angular ,bracketV 55a is advanta-VV geously screwed or otherwiseV fixed at each corner of the base l0 so as to'project up above the base walls Il and function Vas stops for limiting the traverse of the straight edge or the like 28.

An electrical lamp may be adjustably incorporated with the apparatus for illuminating the paper at any required position, together with a suitable switch. Y

VApparatus as above described may be fittedl adjustably or otherwise upon a stand, trestle or Vother support constructed and arranged to enable the drawing board to be tilted to varying anglesand to be raised and lowered to diierent heights. i

I claim: n y

1. Drawing apparatus comprising in combination a relatively stationary base provided with a recess; a circular paper-receiving turn-table rotatably mounted within said recess, and provided with a central pivot, and a plurality of arcuately spaced recesses in its peripheral edge; an antifriction bearing carried by the base receiving said pivot; spaced parallel guides mounted on and projectingV upwardly from said base abovethe plane of said turn-table; a straight edge extending across the turn-table, provided with antifrictionrunners having traveling engagement with the inner sides of said guides, said runners normally retaining the straight edge down upon the face of the turn-table; an adjustable mounting for saidrguides, whereby they may be laterally adjusted toward and ,away from each other to permit assembly of the straightedge between, and

removal of. the same from, Vsaid guides; linear scales onV the guides; anY annular scale at the periphery of the'turnftable; armanually operable brake arranged to frictionally engage said turn-table; a;V manually operable locking pin arranged for engagement in said peripheral recesses of the-turn-table to positively lock it in various angular positions; and a `running bearing vbeturn-table and the base. Y

2. Drawing apparatus according to claim 1,

characterized by the locking pin and the brake being co-axially disposed.

`WILLIAM JAMES EVANS. 

